This invention relates to improvements of the belt drive mechanism in a web feed tractor for printers and more particularly, to a web feed tractor having means for the prevention of meandering of the endless timing belt in the web feed tractor, whereby the timing belt can be driven properly and positively driven along its endless-track with the pins on the outer surface of the belt in precise alignment with and in proper engagement with the marginal perforations in a web being fed by the web feed tractor whereby the web can be properly fed. Thus, the web feed tractor of the invention can be advantageously employed in printers such as computers, word processors and the like information processing machines.